I've done research over the last month and I have found no solution for my problem =(. Posting is usually my last resort, so here goes =).

So, in February, I was out of the country so I had to find a way to unlock my phone at the time and the ipad baseband method was the only way to do so. I BELIEVE my push notifications were working after the unlock so i'm hoping what I did afterwards caused the problem.

So when I returned to Canada in May, I decided to upgrade to the newest version (4.3) and I didnt really care for my unlock since I won't be leaving the country with this phone anymore so I just found a custom ipsw online and upgraded my iPhone with it. The problem arose after this update, I remember having an insane amount of errors while trying to restore with the custom ipsw (10** errors) and i just kept trying via DFU mode over and over again and it suddenly worked so I was pretty happy, until i noticed there is no push notifications =\.

These are the fixes I tried so far:
-I thought perhaps the custom ipsw hacktivated my phone so I created my own ipsw and restored with that, still no push (i tried again afterwards when i upgraded to 4.3.3)
-I tried using SAM to fix it but it doesnt work (again, i thought i may have hacktivated by accident because i dont recall hearing about push problems because of the ipad baseband, only gps problems)
-Just today, i accessed my iphone via SSH and deleted the Lockdown folder so I could see for myself that I am not hacktivated (deleting the folder should verify that, right?) so I used my rogers SIM card (it's a phone locked to Rogers), and i plugged it into itunes, ran the iPusher app, and push notifications STILL doesnt work.

So, hopefully the community has a couple ideas of what I can do, here is a list of some of the information regarding my phone which should be useful.

iPhone 3GS
Old bootrom (i think I should double check if it is necessary for a solution)
6.15.00 ipad baseband
version 4.3.3 (8J2)
MC143C

You need a proper activation in order for iTunes to generate legitimate activation packets for your iPhone. I'm not really sure why you aren't getting push notifications since you have a Rogers SIM in one of their phones, you should have no problem activating without SAM.
I would try again but first delete SAM and ipusher from the phone and delete lockdownd then reboot. After it boots, hook up to itunes to activate and if it successfully activates then download ipusher or ipush test, reboot, then see if its working.

If it still isnt then delete the push app and go to repo.binger.com in cydia and re-dl and install SAM. Reboot (if cydia only resprings then reboot after that). In SAM, de-activate iphone. Reboot. In SAM, revert lockdownd to stock, should get Stockification success. Reboot. In SAM, enable SAM if not already; select By bundle name under Method, scroll to Rogers_ca under Bundle and you should only have 1 SIM ID to choose from under that (302720). Go to More Information and this should also be the first 6 of your IMSI. If so, reboot hook up to itunes and activate. Go back to SAM under More Info to see if wildcard activated. If yes, re-dl ipush test and reboot. (all the reboots seem excessive but this is what worked for me). Run push test and hopefully will be working.

It seems you've tried many things. If you have SHSHs for 4.1 saved, consider downgrading to it with a stock (and not a custom) firmware. Receive error 1015 and exit recovery with TinyUmbrella. Then see if push is working on stock unjailbroken firmware. If so, then at least you know it's a jailbreak thing. If it isn't working still, then I'm not so sure what it is really...

But if you don't have 4.1 SHSHs saved, the best I can suggest is to find a custom fw (or make one if you have a Mac) made by PwnageTool and try again (if you can avoid hacktivating that'd be even better but if so, use SAM again). I'm assuming you used Sn0wbreeze, but if that's not the case, then try vice versa.

It seems you've tried many things. If you have SHSHs for 4.1 saved, consider downgrading to it with a stock (and not a custom) firmware. Receive error 1015 and exit recovery with TinyUmbrella. Then see if push is working on stock unjailbroken firmware. If so, then at least you know it's a jailbreak thing. If it isn't working still, then I'm not so sure what it is really...

Hey, I do have the SHSH blobs for most of the firmwares, including 4.1. However, please correct me if i'm wrong, but isn't it impossible for me to use a stock firmware now because of my ipad baseband? I'll give it a try a bit later, currently trying the previous poster's suggestion of using SAM

EDIT:

Originally Posted by sprackleor

You need a proper activation in order for iTunes to generate legitimate activation packets for your iPhone. I'm not really sure why you aren't getting push notifications since you have a Rogers SIM in one of their phones, you should have no problem activating without SAM.
I would try again but first delete SAM and ipusher from the phone and delete lockdownd then reboot. After it boots, hook up to itunes to activate and if it successfully activates then download ipusher or ipush test, reboot, then see if its working.

If it still isnt then delete the push app and go to repo.binger.com in cydia and re-dl and install SAM. Reboot (if cydia only resprings then reboot after that). In SAM, de-activate iphone. Reboot. In SAM, revert lockdownd to stock, should get Stockification success. Reboot. In SAM, enable SAM if not already; select By bundle name under Method, scroll to Rogers_ca under Bundle and you should only have 1 SIM ID to choose from under that (302720). Go to More Information and this should also be the first 6 of your IMSI. If so, reboot hook up to itunes and activate. Go back to SAM under More Info to see if wildcard activated. If yes, re-dl ipush test and reboot. (all the reboots seem excessive but this is what worked for me). Run push test and hopefully will be working.

i JUST finished doing this step by step (did a reboot on every step), and i'm sad to say that my push still does not work, will try downgrading to 4.1 later tonight.

NVM haha alright, i restored to stock 4.1 firmware and push notifications work now via the iPusher app.
i'm facepalming a bit cause i always thought i could never do a stock restore again because of the fact that i'm on an ipad baseband, what a silly misconception, thank you very much everybody, i'll keep updating as i jailbreak + reupdate to 4.3.3 to see if i lose my push notification along the way, but thank you again ^^

EDIT:

tried updating to 4.3 but got stuck on the 1015 loop and iREB and tiny umbrella couldnt kick it out so i just gave up and stuck to 4.1, jailbroke, and push still works, so this is officially solved =), dont know what broke it in the first place though =\

+1. this is bc TinyUmbrella is not capable of the exit recovery mode option that is necessary after receiving error 1015 when on fw 4.2.1 and above. It works on 4.1 and below so you can use stock fw as long as you have SHSHs to restore with.

i JUST finished doing this step by step (did a reboot on every step), and i'm sad to say that my push still does not work, will try downgrading to 4.1 later tonight.

Thats too bad that it didn't work for you, I dont see why. I'm on bb 5.13.04 but that shouldn't matter. When I got the SAM method to work, it took me maybe 6-7 tries to get it right. You have to get the IMSI for SIM and SAM to match up with the carrier in order to get wildcard activated. For me, my SIM IMSI is 301xxx which is nowhere near 302720 (it was orig locked to Rogers as well). Eventually, I found the correct sequence in order for the spoofed IMSI to stick as the instructions for using SAM are lacking and not intuitive.
So if you are really wanting to get back up to 4.3.3 from 4.1 (I know I would as you lose quite a bit) which you know you can get back to, maybe try again. Or just live with 4.1 for a couple more months until iOS 5 comes out. It will be interesting to see where the bb's start in iOS 5.